Test bank for principles of biochemistry 5th edition by moran

A carboxylate, amino, double B carboxylate, amino, enzyme C amino, carboxylate, phosphate D amino, carboxylate, peptide Answer: D Page Ref: Section 1-3 10 Sugars such as glucose are mono

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Principles of Biochemistry, 5e (Moran/Horton/Scrimgeour/Perry/Rawn)

Chapter 1 Introduction to Biochemistry

1) Wohler showed that a chemical found only in living organisms can be made from inorganic substances when he synthesized

A) Ammonium cyanate

B) Amino acids

C) Urea

D) Uric acid

Answer: C

Page Ref: Section 1-1

2) The lock-and-key theory described the action of

A) enzymes as keys that fit different chemicals

B) substrates as keys that fit different enzymes

C) enzymes as locks that fit other enzymes

D) substrates as locks that fit different enzymes

Answer: B

3) According to Crick's Central Dogma of molecular Biology, there can be NO transfer of information from

A) DNA to RNA

B) RNA to RNA

C) RNA to protein

D) protein to RNA

Answer: D

4) What is the correct order in which these key breakthroughs in biochemistry occurred?

I Watson and Crick DNA structure

II Crick Central dogma

III Avery, MacLeod and McCarty DNA work on Streptococcus

IV Widespread use of computers

A) I, II, III, IV

B) III, I, II, IV

C) II, I, III, IV

D) IV, III, I, II

Answer: B

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5) Which elements account for more than 97% of the weight of most organisms?

A) C, H, N, Mg, O, S

B) C, H, N, O, P, S

C) C, H, N

D) Fe, C, H, O, P

E) Ca2+, K+, Na+, Mg2+,

Cl-Answer: B

6) Which linkage(s) occur extensively in nucleotides?

A) Amide

B) Phosphoanhydride

C) Phosphate ester

D) Ether

E) Both B and C above

Answer: E

7) Which functional group is shown?

A) Primary amine

B) Acyl

C) Amide

D) Anhydride

E) Nitrile

Answer: C

8) Proteins in biological membranes may be

A) porous

B) attached to the membrane surface

C) span the membrane

D) all of the above

E) B and C only

Answer: D

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9) A dipeptide forms when a functional group of one amino acid reacts with the functional group of another amino acid to form a bond

A) carboxylate, amino, double

B) carboxylate, amino, enzyme

C) amino, carboxylate, phosphate

D) amino, carboxylate, peptide

Answer: D

10) Sugars such as glucose are monomers of polysaccharides that are linked together when covalent bonds form between one group of one sugar to the same group on another sugar

A) ester

B) carboxyl

C) amino

D) hydroxyl

Answer: D

11) Which statement about cellulose is false?

A) It is the most abundant polysaccharide in nature

B) Its monomers are joined by glycosidic bonds

C) It is present in the stems of flowering plants

D) The hydroxyl groups of neighboring cellulose molecules interact to form strong, insoluble fibers

E) It is a branched polymer of glucose

Answer: E

12) When Keq of a reaction = 1, then

A) the forward reaction is faster than the reverse reaction

B) the reverse reaction is faster than the forward reaction

C) the forward and reverse reaction rate constants are equal

D) more products are formed than reactants

E) fewer products are formed than reactants

Answer: C

13) Most of the energy required for life on Earth is supplied by

A) geothermal energy

B) the sun

C) cosmic radiation

D) the conversion of ADP to ATP

E) mechanical energy

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A) It is dependent on the concentrations of both products and reactants.

B) It is dependent only on the concentrations of the reactants

C) It is dependent only on the concentrations of the products

D) It is not dependent on the concentrations of either the products or reactants

Answer: A

15) Which statement is true about a reaction with an equilibrium constant, Keq, equal to 1000? A) The forward rate constant is 1000 times greater than the reverse rate constant

B) The forward rate constant is 3 times greater than reverse rate constant

C) The forward rate constant is 1000 times smaller than the reverse rate constant

D) The forward rate constant is 3 times smaller than the reverse rate constant

E) There is not enough information given to compare the forward and reverse rate constants Answer: A

16) If a reaction is at equilibrium, what is the free energy change?

A) It is always positive

B) It is always negative

C) It could be either positive or negative depending on the reaction

D) It equals zero

Answer: D

17) Which statement is true?

A) If DG is negative, then the rate of the reaction will be fast

B) If DG is positive, then the rate of the reaction will be fast

C) If DG is negative, then the rate of the reaction will be slow

D) If DG is positive, then the rate of the reaction will be slow

E) The reaction rate is independent of DG

Answer: E

18) The study of the energy changes during metabolic reactions is called

A) bioinformatics

B) metabodynamics

C) thermometrics

D) bioenergetics

E) biological heat dynamics

Answer: D

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19) A spontaneous chemical reaction always has a change.

A) positive Gibb's free energy

B) negative Gibb's free energy

C) positive enthalpy

D) negative enthalpy

E) positive entropy

Answer: B

20) Prokaryotes are valuable tools for biochemists because

A) E coli is well-studied and typical of prokaryotes

B) they contain as many genes as eukaryotic cells

C) many of their chromosomes are sequenced

D) they are not very diverse organisms

E) All of the above

Answer: C

21) Which cellular component carries out oxidation reactions, some of which produce hydrogen peroxide?

A) Peroxisomes

B) Mitochondria

C) Chloroplasts

D) Lysosomes

E) Vacuoles

Answer: A

22) Why is it important that the enzymes in lysosomes are more active at acidic pH than at neutral pH?

A) Since lysosomes are primarily found in the stomach acid of mammals, their pH dependence allows for maximum efficiency for the digestion of foodstuffs

B) It prevents their diffusion out of the lysosomes

C) It maximizes the interaction with their substrates which are always bases

D) It prevents them from accidentally degrading the macromolecules in the cytosol

E) It allows for regulation of their uptake by the mitochondria

Answer: D

23) Molecules from living cells cannot be synthesized outside of living cells

Answer: FALSE

24) Fermentation in the absence of cells demonstrated that metabolic processes were chemical in

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Answer: TRUE

26) The modified lock-and-key theory of enzyme action proposed by Emil Fischer has been completely replaced by more modern ideas of catalysis

Answer: FALSE

27) Enzymes are not as efficient as most catalysts used in organic chemistry, since they must function at body temperature

Answer: FALSE

28) Bioinformatics has permitted rapid advances in our understanding of structural

macromolecules from living cells

Answer: TRUE

29) The role of DNA as the genetic material was confirmed by transforming Streptococci in experiments performed several years after the famous Watson and Crick description of DNA structure

Answer: FALSE

30) Crick referred to the flow of information from nucleic acid to protein as the Central Dogma Answer: TRUE

31) Functional groups describe one or more portions of organic compounds found in living cells Answer: TRUE

32) A phosphate ester contains a phosphate functional group

Answer: TRUE

33) Under most biological conditions, acid groups and amino groups are fully protonated

Answer: FALSE

34) Water is often a product when monomers join to form a macromolecule

Answer: TRUE

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35) Mr is the mass of a molecule relative to 1/12 the mass of an atom of the most common isotope of carbon

Answer: TRUE

36) Biochemists describing the molecular weight of a protein really mean the atomic weight in grams

Answer: FALSE

37) The absolute molecular mass of macromolecules is given in daltons, where 1 dalton = 1 atomic mass unit

Answer: TRUE

38) A peptide bond is formed by the condensation of different functional groups from two amino acids

Answer: TRUE

39) The conformation of a protein enzyme determines whether it is functional or not

Answer: TRUE

40) Lysozyme is an enzyme with a cleft or depression at its active site

Answer: TRUE

41) The Haworth projection of the ring form of a monosaccharide always shows a flat plane with one edge projecting out of the page (using thicker lines)

Answer: TRUE

42) Sugars with six carbons are the only ones capable of forming a ring structure as shown in a Haworth projection

Answer: FALSE

43) ATP contains both phosphoester and phosphoanhydride linkages

Answer: TRUE

44) A phosphodiester linkage in DNA contains two phosphorous atoms

Answer: FALSE

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45) Lipids aggregate to form bilayers because some lipid molecules are hydrophobic and other lipid molecules are hydrophilic

Answer: FALSE

46) Thermodynamics and its laws are obeyed by living cells

Answer: TRUE

47) The tendency of a metabolic reaction to proceed is due to the free energy of both the

reactants and products as well as the change in randomness of that reaction

Answer: TRUE

48) Biochemical reactions are more likely to proceed if the reaction has an increase in enthalpy (△H) and a decrease in entropy ( S).

Answer: FALSE

49) All prokaryotic cells are about 1/10 the size of an average eukaryotic cell or smaller

Answer: FALSE

50) All cells have kept the same general patterns of metabolism, a very similar genetic code and the same monomers or residues

Answer: TRUE

51) Eukaryotes include plants, animals and bacteria

Answer: FALSE

52) The only reason phages are not considered to be cells is because they do not contain a plasma membrane

Answer: FALSE

53) Diffusion is an adequate means of distributing nutrients in prokaryotic cytoplasm because they have more surface area than volume compared to most eukaryotes

Answer: TRUE

54) Eukaryotic cells are distinguished from prokaryotes by their usually larger size, a complex cytoskeleton and membrane-bounded organelles

Answer: TRUE

55) Chloroplasts are organelles found in plants, algae and some protists and are the site of

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photosynthesis

Answer: TRUE

56) The endoplasmic reticulum is the major site of RNA synthesis and the site of assembly of ribosomes

Answer: FALSE

57) The nuclear envelope is a membrane that surrounds the nucleus and is continuous with the endoplasmic reticulum

Answer: TRUE

58) Ribosomes on the surface of rough endoplasmic reticulum are the site of ATP synthesis Answer: FALSE

59) The Golgi apparatus consists of flattened, fluid-filled, membranous sacs and is responsible for chemical modification and sorting of some biomolecules

Answer: TRUE

60) Mitochondria are the main sites of energy transduction in aerobic eukaryotic cells

Answer: TRUE

61) The mitochondria and Golgi apparatus are two organelles which originated from bacteria and were incorporated into eukaryotic cells via symbiosis

Answer: FALSE

62) In an animal cell, DNA can be found only in the nucleus

Answer: FALSE

63) Actin has been shown to be one of the most evolutionarily conserved proteins It is present in all eukaryotic cells and frequently is the most abundant protein in the cell

Answer: TRUE

64) The mitotic spindles are formed from microtubule proteins

Answer: TRUE

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65) The filament fibers in the cytoskeleton are composed primarily of carbohydrate molecules Answer: FALSE

66) The diffusion of large molecules such as enzymes is significantly slowed by the presence of the cytoskeleton

Answer: TRUE

67) In eukaryotic cells lysosomes are specialized digestive vesicles with a highly acidic interior Answer: TRUE

68) The process of cell division that occurs in the tissues is called mitosis

Answer: TRUE

69) Photosynthesis involves capturing energy from light that is then used to drive the formation

of carbohydrates from carbon dioxide and water

Answer: TRUE

70) The chemical name for ATP is alanine triphosphate

Answer: FALSE

71) Absolute zero is equal to 0°C

Answer: FALSE

Page Ref: 1-Appendix

72) One Angstrom is equal to 1 × 10-10 meters

Answer: TRUE

Page Ref: 1-Appendix

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